Which statement is correct regarding HF NBDP under GMDSS?

Correct Answer: Option A — Safety communications by direct-printing telegraphy should be in the ARQ mode when communicating with the U.S. Coast Guard or other coast stations on channels that they normally guard.

Under USCG National Maritime Center examination standards, the accepted correct answer is: Safety communications by direct-printing telegraphy should be in the ARQ mode when communicating with the U.S. Coast Guard or other coast stations on channels that they normally guard..